Chapter 114- Refrigerants

Question 1

Liquid refrigerants are defined as

Answer 1

Liquids that, atmospheric pressure, have a boiling point considerably lower than that of water

Question 2

There are six groups of refrigerant

Answer 2

B1, b2, b3, a1, a2, a3

Question 3

The B group is characterized by its

Answer 3

Toxicity

Question 4

The A group is characterized by its

Answer 4

Low toxicity

Question 5

The number determines its

Answer 5

Flammability

Question 6

A1 is defined as

Answer 6

Non toxic, non flammable

Question 7

A2 is defined as

Answer 7

Flammable, low toxicity

Question 8

A3 is defined as

Answer 8

Low toxicity, highly flammable

Question 9

B1 is defined as

Answer 9

Highly toxic an non flammable

Question 10

B2 is defined as

Answer 10

Flammable and highly toxic

Question 11

B3 is defined as

Answer 11

Highly flammable, highly toxic

Question 12

Ideal refrigerants have these qualities

Answer 12

Low boiling point at atmospheric pressure
Low condensing pressure
An inoffensive odour
A non poisonous nature
Non corrosive action on metals
Nonflammable and non explosive nature when mixed with air
Reasonable price

Question 13

Thermodynamic properties include

Answer 13

Pressure
Temperature
Volume
Density
Enthalpy
Entropy

Question 14

What is the pressure temperature relationship of refrigerants

Answer 14

The saturation temperature of a liquid in a closed vessel can be raised or lowered by raising or lowering the pressure in a vessel.

Question 15

What are standard conditions of a refrigerant

Answer 15

Standard evaporator temperature of -15 degrees Celsius

Standard condenser temperature of 30 degrees Celsius

Question 16

Specific volume is defined as

Answer 16

It is necessary to know the specific volume of a refrigerant while it is a liquid or a vapour under conditions required in the refrigerator it’s specific volume is the the change in volume between states

Question 17

Density is defined

Answer 17

The density of a liquid refrigerant, required to know the size of valves and piping in a refrigerator. Expressed in kg/ meters cubed

Question 18

Enthalpy is defined as

Answer 18

Sensible heat in a liquid

Sensible heat plus latent heat in a vapour

Question 19

Refrigerating effect

Answer 19

The effect of heat being taken away from the surroundings so that cooling may take effect, vapour to a gas requires latent heat energy this is what causes the cooling effect in a refrigerator

Question 20

Physical properties of refrigerants

Answer 20

Miscibility
Leakage tendency
Odour
Toxicity 
Flammability/ explosiveness
Moisture reaction

Question 21

Miscibility is defined as

Answer 21

The ability of oil to be absorbed into a refrigerant and vice versa is miscibility

Question 22

Leakage tendency is defined as

Answer 22

The leakage tendency of a liquid may include factors like
Operating pressure
Viscosity
Density
Molecular mass of the refrigerant
Larger the molecule, the less of a chance it has to escape
Fat kids can't run
for long

Question 23

Odour is

Answer 23

What you smell
Idiot
Used to detect is a refrigerant leak is taking place

Question 24

When a halide torch is us for leak detection what should be done

Answer 24

Provide ample ventilation

Question 25

Toxicity is defined as

Answer 25

When e posed to a flame the may react and decompose forming highly toxic vapours, or may be highly toxic to begin with

Will fucking kill you

Question 26

Moisture reaction must be avoided for two reasons

Answer 26

May cause ice to form between valve and valve seat
Could result in corrosion
Sludge forming
Deterioration of the motor insulation